 So the guest is presumed to be thirsty and in need of some drink after the trip . In that case , I guess , in return , the guest doesn't have to drink it if he wouldn't like it . 
 It wouldn't be considered rude behavior if he doesn't even take a single drop . But he'd better receive the teacup with both hands and bow his thanks when the cup is brought before his face . When the host pours hot water into his cup , he may also choose to tap his index finger on the table , meaning " Thanks " . No matter if he likes it or not , it is impolite if he doesn't even lay a finger on the cup . 